Eleven and twelve were alive, too, but looked much the same. If anything, their bioluminescent skies were even further degraded, so that their light was even weaker.
What I’d eventually concluded about the worldlet Saul had found was that it had initially been set up with very sophisticated biotechnology, which had gradually gone completely to pieces. Its energy supply had initially been electrical and thermal, and the light-producing systems had been organic—although they were not organisms capable of independent life. Over a very long time, possibly running to several millions of years, entropy had done its work and the carefully engineered artificial organics had gradually given way to real organisms, which did retain some of the features of the artificial system, but not so efficiently.
What had happened, therefore, was effectively a devolution or degeneration from artificial systems to living ones. I know that seems almost crazy, given that we generally think of living systems being far more ordered than non-living ones, but the builders’ biotechnics had been more sophisticated than living systems. Even something as primitive (in these terms) as the Tetrax artificial photosynthesis systems up on level one would, if left to its own devices, eventually give way to “natural” grass. Think of it not so much as non- life degenerating into life, but as the delicately-bred plants in a garden, adapted not simply to reproduce themselves but also to serve the purposes of the gardeners, gradually evolving into coarser—but inherently hardier—weeds.
A mixture of guesswork and inference suggested to me that some of the old inhabitants of Skychain City were being relocated to lower levels, where they were being herded into the ruins of ancient and long derelict cities to begin the work of refurbishing them for their new would-be masters. For the Tetrax, especially, it must have been like being sent back to the Stone Age. As we crossed a particularly bleak plain on twelve I wondered whether there was some kind of testing going on. Maybe the invaders wanted to see whether the Tetrax were clever enough to find out how the systems built into Asgard’s structure could be made to function again, even after a vastly long period of disuse and decay.
Further down, the rot that had claimed the higher habitats seemed not to have set in—or not to have progressed so far. But there were other complications.
Until we reached fifteen I had assumed that all the levels would have much the same atmosphere. The atmospheres of almost all humanoid homeworlds are very similar indeed, the relative percentages of nitrogen, oxygen, and carbon dioxide being a cleverly-maintained optimum. Planetary atmospheres, of course, are the creation of life, and because all the humanoid homeworlds share the same chemistry of life, they share the same ideal conditions. Their ecospheres adapt to produce and conserve those conditions, in much the same way that homeostatic mechanisms within endothermic organisms produce a constant internal temperature.
There are one or two galactic humanoid species who breathe air that the rest of us would find uncomfortable, but for precisely that reason they aren’t fully integrated into the galactic community. There are life-systems that have alternative chemistries, but they shape up very differently from the kind of life-system that produces humanoids. You do get life, of a sort, in the atmospheres of gas giant planets—even gas giants as cold as Uranus—but it doesn’t produce anything like the range of organisms that DNA can produce, and as far as I knew no one had ever found evidence of anything in such a system as intelligent as an insect, let alone a man.
Thus, I was very surprised to find that in a big airlock on level fifteen, our little party boarded a vehicle which looked more like a gigantic bullet or a wheeled starship than a car, and that when we went out into the open, we found ourselves in a real pea-souper of an atmosphere.
For a few minutes, I simply watched in astonishment as the coloured fog roiled around the thick windows, stirred into activity by the velocity of our passage. It was a dingy green colour, lit from above by a sky no more than fifteen metres above us. The green wasn’t uniform, though: there were coiling wraiths of purple and indigo, like gaseous worms, and bigger, paler shapes that reminded me of old- fashioned images of immaterial spooks and spectres.
I could tell that Jacinthe Siani had seen it before, but not often enough to get entirely blase about it. Sky-blue and the troopers were as bored as they could be, though.
“What is it?” I asked Sky-blue.
“Mostly methane, hydrogen, and carbon oxides,” said Sky-blue, morosely. “Some helium, many longer-chain carbon molecules. Very high pressure. We have to be careful with the locks. If the atmospheres get mixed, they react. Sometimes explosively. We don’t know any other way through. Our maps are incomplete. We were fortunate to be able to locate a way up as quickly as we did; an environment like this might have been a barrier for many generations. The first one our forefathers discovered was the boundary of their empire for a long time, but we can now move about freely in such habitats, and we find certain uses for them.”
“Is there life here?”
“Of a sort. Nothing that troubles us.”
“I don’t suppose you have a theory as to why your ancestors should fill some of their cave-systems with alien atmospheres?”
Before he could answer, the older man cut in with a few sharp remarks in his own tongue. Sky-blue favoured me with a dirty look, and I figured that he’d just been reminded that I was a spy and an enemy. I decided that it would be diplomatic to ask fewer questions.
By the time we left fifteen, I was ready for more surprises. Indeed, I was eager for them, if only to take my mind off what might be awaiting me below. For that reason, all the levels I numbered in the twenties were disappointments. They certainly weren’t dead, and I didn’t get the impression that they were markedly decayed, but the territory we crossed was empty. The skies were bright, and the vegetation seemed reasonably lush, but there was no evidence of sophisticated machinery except for the vehicles on the road, and the only sentients I saw were the pale-skinned invaders.
I could see plenty of pillars holding up the ceilings, but I couldn’t see any blocks filled out with doors and windows. I knew, though, that we were seeing only the tiniest slice of each habitat, and that every one of them would surely be as big, and might well be as various, as an Earthly continent. It was as though I was trying to judge the nature and complexity of the Earth from a twenty-kilometre drive across a randomly chosen part of Canada. The best sights these levels had to offer might be awesome indeed, but it was entirely possible that the invaders had never yet caught a glimpse of them, having only skated quickly across the surface, more eager to find doorways to other levels than to explore fully those which appeared harmless and useless to them.
When we stopped to sleep, at a way station on what I took to be level twenty-nine, I was beginning to fear that Asgard might not have much more to show me. Wouldn’t it be ghastly, I thought, if the Centre turned out to be no more exotic than Skychain City—or the microworld Goodfellow? There is no more horrible way that any mystery can be resolved than by dissolution into ironic anti-climax.
I consoled myself with the thought that we were a long, long way from the Centre yet—and with the knowledge that the reason I was being taken on this little trip to the heartland of Invaderdom was that I had already been shown proof that there were more things in Asgard, as in Heaven, than had hitherto been dreamt of in the invaders’ poverty- stricken philosophy.
But could I, I wondered, interest them enough to persuade them to let me live?
16
The levels I numbered in the thirties were much brighter and more crowded than those in the twenties. Every time we emerged from one of the buildings that housed the connecting shafts, we came out into thriving city streets—wide roads with floor-to-ceiling facings, pavements, shops. This, I inferred, was the heartland of the invader empire; these were levels they had colonized in the distant past. I couldn’t tell which was their home level, and my companions were not answering questions. Sky-blue and the senior officer had been arguing again, and Sky-blue was rather tight- lipped. Jacinthe Siani was keeping her distance from me, probably because she wanted to impress upon her new friends that she was solidly on their side.